A pandemic is a global disease outbreak. An influenza pandemic occurs when a new influenza A virus emerges for which there is little or no immunity in the human population, begins to cause serious illness and then spreads easily person-to-person worldwide.

Historically, the 20th century saw 3 pandemics of influenza:

• 1918 influenza pandemic caused at least 500,000 U.S. deaths and up to 40 million deaths worldwide
  
  
• 1957 influenza pandemic caused at least 70,000 U.S. deaths and 1-2 million deaths worldwide
  
  
• 1968 influenza pandemic caused about 34,000 U.S. deaths and 700,000 deaths worldwide

Characteristics and challenges of a pandemic

1. Rapid Worldwide Spread

• When a pandemic influenza virus emerges, its global spread is considered inevitable.
  
  
• Preparedness activities should assume that the entire world population would be susceptible.
  
  
• Countries might, through measures such as border closures and travel restrictions, delay arrival of the virus, but cannot stop it.
  

2. Health Care Systems Overloaded

• Most people have little or no immunity to a pandemic virus. Infection and illness rates soar. A substantial percentage of the world’s population will require some form of medical care.
  
  
• Nations unlikely to have the staff, facilities, equipment and hospital beds needed to cope with large numbers of people who suddenly fall ill.
  
  
• Inadequate supplies antivirals drugs, the two most important medical interventions for reducing illness and deaths, are of particular concern.
  
  
• Death rates are high, largely determined by four factors: the number of people who become infected, the virulence of the virus, the underlying characteristics and vulnerability of affected populations and the effectiveness of preventive measures.
  
  
• Past pandemics have spread globally in two and sometimes three waves.
  

3. Medical Supplies Inadequate

• The need for vaccine is likely to outstrip supply.
  
  
• The need for antiviral drugs is also likely to be inadequate early in a pandemic.
  
  
• A pandemic can create a shortage of hospital beds, ventilators and other supplies. Surge capacity at non-traditional sites such as schools may be created to cope with demand.
  
  
• Difficult decisions will need to be made regarding who gets antiviral drugs and vaccines.
  

4. Economic and Social Disruption

• Travel bans, closings of schools and businesses and cancellations of events could have major impact on communities and citizens.
  
  
• Care for sick family members and fear of exposure can result in significant worker absenteeism.

Education and outreach are critical to preparing for a pandemic. Understanding what a pandemic is, what needs to be done at all levels to prepare for pandemic influenza, and what could happen during a pandemic helps us make informed decisions both as individuals and as a nation. Should a pandemic occur the public must be able to depend on its government to provide scientifically sound public health information quickly, openly and dependably. For additional information on pandemic influenza visit: www.pandemicflu.gov.

(Source: PandemicFlu.Gov)